Structure of the filamentous phage pIV multimer by cryo-electron microscopy.

Abstract

The homo-multimeric pIV protein constitutes a channel required for the assembly and export of filamentous phage across the outer membrane of Escherichia coli. We present a 22 A-resolution three-dimensional reconstruction of detergent-solubilized pIV by cryo-electron microscopy associated with image analysis. The structure reveals a barrel-like complex, 13.5 nm in diameter and 24 nm in length, with D14 point-group symmetry, consisting of a dimer of unit multimers. Side views of each unit multimer exhibit three cylindrical domains named the N-ring, the M-ring and the C-ring. Gold labeling of pIV engineered to contain a single cysteine residue near the N or C terminus unambiguously identified the N-terminal region as the N-ring, and the C-terminal region was inferred to make up the C-ring. A large pore, ranging in inner diameter from 6.0 nm to 8.8 nm, runs through the middle of the multimer, but a central domain, the pore gate, blocks it. Moreover, the pore diameter at the N-ring is smaller than the phage particle. We therefore propose that the pIV multimer undergoes a large conformational change during phage transport, with reorganization of the central domain to open the pore, and widening at the N-ring in order to accommodate the 6.5 nm diameter phage particle.

02040'04'06'08'10'12'14'16
Citations per Year

152 Citations

Semantic Scholar estimates that this publication has 152 citations based on the available data.

See our FAQ for additional information.

Cite this paper

@article{Opalka2003StructureOT, title={Structure of the filamentous phage pIV multimer by cryo-electron microscopy.}, author={Natacha Opalka and Roland Beckmann and Nicolas Boisset and Martha N Simon and Marjorie Russel and Seth A Darst}, journal={Journal of molecular biology}, year={2003}, volume={325 3}, pages={461-70} }